Aug. 23--A day after President Donald Trump's former lawyer implicated him while pleading guilty to breaking campaign finance laws, Republican U.S. Rep. Peter Roskam tried to both voice support for elements of Trump's agenda while calling his behavior a "mixed bag."

Roskam said Trump has "demonstrated a lot to be desired as it relates to being forthcoming." His Democratic challenger, Sean Casten, meanwhile, called the president "a walking disaster."

The two candidates appeared before the Chicago Tribune Editorial Board on Wednesday, sparring on an array of policy issues, including taxes, health care and immigration. But Trump -- and the recent developments in federal court -- loomed over the issues in the race for the pivotal suburban 6th Congressional District, which voted for Democrat Hillary Clinton two years ago.

"I'm aware, obviously, of the environment in which I'm operating," Roskam said.

The Tuesday guilty plea of Trump's personal lawyer, Michael Cohen, and the conviction of his former campaign manager, Paul Manafort, on tax and bank fraud charges were "significant," Roskam told reporters after the meeting. The Wheaton Republican congressman said the question now becomes how special counsel Robert Mueller proceeds with his investigation into Russian meddling in the 2016 election. Roskam said he fully supports Mueller's investigation.

"Does it bring me any joy to be having this discussion about the president of the United States? No," Roskam said.

Casten said after the editorial board meeting that he believes Trump is "hands down the worst president of my lifetime. This guy is a walking disaster. The sooner he's out of office the better."

But the political newcomer and businessman from Downers Grove stopped short of saying Trump should be impeached. Instead, he said Democrats' best way to combat Trump is to take back control of the House so they can provide a counterweight and more oversight of the president.

Roskam is trying to win a sixth term in Congress. He's a veteran politician from Wheaton who started in the Illinois House in Springfield in the mid-1990s and rose to be part of former House Speaker John Boehner's leadership team in Washington.

Casten is playing a central role in Democrats' national efforts to flip control of the House, having emerged from a crowded, competitive primary field in March. Democrats see the November election as a rare opportunity to topple an established congressman such as Roskam even though his home base of DuPage County long has been a power center for Illinois Republicans. In 2016, Hillary Clinton prevailed over Trump in the district by 7 percentage points.

It's against that backdrop that Roskam has backed elements of Trump's agenda, including tax policy, his support of the military and the appointment of Supreme Court Justice Neil Gorsuch. Asked on Wednesday if Trump is ethical, Roskam cited Illinois' most famous president using a tale most often told about George Washington.

"Never telling a lie, Abraham Lincoln, is that the standard?" Roskam said of Trump. "No, I wouldn't put him in that category."

And he said local voters, as they have in the past, can separate their opinions about Trump from their policy preferences on matters such as taxes and health care.

"This is a district that is discerning and capable of separating out different responsibilities," Roskam said.

Casten, meanwhile, didn't directly answer whether he'd vote for House Democratic leader Nancy Pelosi for speaker if his party takes control of the chamber.

"I want to understand what the choices are," he said.

The two candidates have debated before, most recently at a forum Fox-32 broadcast last month. That matchup showed they agree about almost nothing and are comfortable attacking each other. Wednesday's meeting was more subdued. They spent much of it locked in a wonky discussion about taxes, health care and immigration -- topics on which they sharply disagree.

Roskam helped write Republicans' federal tax overhaul last year and said the benefits of cuts for individuals and businesses are worth the costs.

"We borrowed money to get a simpler and updated tax code," Roskam said, later adding: "The other thing that we get is a growing economy."

"There's a lot of words there, I disagree with almost all of them," Casten replied. He contends that giving companies tax breaks is no guarantee they'll create jobs.

On health care, Casten criticized Republicans for "a complete dismantling" of the Affordable Care Act. Roskam countered that the ACA fell far short of what was promised.

"We were told if you liked your doctor you could keep your doctor, that didn't happen," Roskam said. "We were told if you liked your coverage you could keep your coverage, that didn't happen." He repeated his view that Casten wants to "protect, defend and expand" the ACA.

And Roskam sought to deflect Casten's criticism that he hasn't held enough town hall meetings, saying the country is "running above idle right now" and such large-scale gatherings aren't productive.

Instead, Roskam said he's held hundreds of smaller events and meetings at businesses, schools and other places to meet with thousands of constituents over time.

"We need less drama. We need less hyperbole. We need less shouting. And we need more of an ability to work with other people on the other side of the aisle," Roskam said. "And my experience is that if you're sitting down in a smaller group, even if somebody is disagreeing with you, you can actually have a discussion."

Casten pledged to hold four town hall meetings per year if elected, saying he was "truly baffled by Peter's thought process" on the topic.

"The last time you had a town hall, Lehman Brothers existed, Uber didn't, and America had never known a black president," Casten said.

Roskam, 56, is no stranger to an expensive, closely watched race with national implications. Twelve years ago, he narrowly defeated now-U.S. Sen. Tammy Duckworth, bucking that year's midterm trend of GOP losses as Democrats took back control of the U.S. House. Duckworth at the time had the backing of party heavyweights such as U.S. Sen. Dick Durbin and now-Mayor Rahm Emanuel, and her story of her Black Hawk helicopter being shot down in Iraq was fresh in voters' minds.

Casten, 46, could be bolstered by the national Democratic tail winds that may accompany the midterm elections.

Showing the heavy interest in the race, national groups have begun spending big money in the 6th District. The Congressional Leadership Fund aligned with Republican House Speaker Paul Ryan has run a pair of TV ads in the district bolstering Roskam and criticizing Casten. And the group has set up a field office to talk to voters directly. That's on top of the American Chemistry Council's early campaign ads in support of Roskam.

Roskam had $2.3 million in the bank, but Vice President Mike Pence made a fundraising stop for him last month to help him add to that total. Casten, meanwhile, had $647,000 on hand.

But while campaign fundraising can be more difficult for challengers than sitting congressmen, Casten has been able to use his personal wealth to help pay for his campaign so far. Records show he put $630,000 into his bid before the primary, and on Wednesday he announced his first TV ad of the campaign.

The 30-second spot tries to defend Casten's business record from the GOP attack ads. "Peter Roskam, using the Trump playbook: lies and dishonesty," a narrator says in Casten's commercial.